Weaning From Mechanical Ventilation
Conditions
Keywords
Weaning, mechanical ventilation, Proportional Assist Ventilation
Brief summary
The study hypothesis is that reducing patient-ventilator asynchrony will reduce time required to wean from mechanical ventilation. The purpose of this pilot study is (1) to assess study feasibility in terms of recruitment, protocol adherence and efficacy of the intervention for reducing asynchrony, (2) to assess baseline rates of asynchrony and outcomes in the control arm in order to perform sample size calculations, if needed, for further, larger studies designed to detect differences in weaning time in specific, predefined populations and (3) to examine how often ineffective triggering (and therefore reduced ventilator respiratory rate) at higher levels of pressure support lead to a false conclusion that higher levels of support are needed to diminish respiratory distress.
Detailed description
Previous research has shown that approximately twenty-five percent of patients capable of triggering the ventilator in assisted modes have high rates of patient-ventilator asynchrony, and that such patients have a longer duration of mechanical ventilation. It is not known whether asynchrony is a cause of weaning failure or simply a marker of more severe respiratory failure. The most common type of asynchrony, ineffective triggering, may be both a marker of respiratory disease and a cause of delayed weaning. During ineffective triggering, the patient's inspiratory effort fails to trigger a ventilator breath, and thus the respiratory rate displayed on the ventilator underestimates the patient's true, intrinsic respiratory rate. Since ineffective triggering is more common at higher levels of pressure support than lower levels, an increase in respiratory rate during weaning of pressure support may indicate the development of respiratory distress or simply the abolition of ineffective triggering. Ineffective triggering may also cause delayed weaning because respiratory muscle energy is wasted on non-supported breaths. Proportional assist ventilation (PAV) is an FDA- and HPB-approved mode of ventilation in which the ventilator applies pressure in proportion to patient effort. Using PAV, patient-ventilator interaction may be optimized and ineffective triggering greatly reduced. Since the patient and ventilator respiratory rates are generally equivalent, a reduction in respiratory rate with increasing ventilatory support is less likely to be false positive indication of the need for greater assistance. In this study, patients with difficulty weaning from mechanical ventilation will be randomized to weaning with one of two weaning protocols: Proportional Assist Ventilation (PAV) weaning algorithm (intervention arm) vs. Pressure Support Ventilation (PSV) weaning algorithm (control arm).
Interventions
Sponsors
Medtronic - MITG
University of Western Ontario, Canada
London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Age 18 years or greater * Mechanically ventilated patients who are ready to begin weaning according to prespecified eligibility criteria, and tolerate thirty minutes of pressure support ventilation (PSV), but are not ready for extubation, defined as an frequency to tidal volume (f/Vt) greater-than (\>) 105 after two minutes of constant positive airway pressure (CPAP) * Reason for intubation partially or completely reversed
Exclusion criteria
* Tolerating PSV 5 greater-than (\>)2 hrs (Weaned) * Plan to extubate today * Extubated today * Considering Withdrawal of life support (less-than (\<)48hrs) * Neurosurgical patient * High SC injury/ progressive NMD * Tracheostomy at time of ICU admission * Has met all weaning eligibility and been on Pressure Support Ventilation (PSV) \>36 hours
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Duration of weaning | From time of randomization up to 28 days | Duration of weaning will be assessed as (a) the time elapsed from study randomization until the patient successfully passes a spontaneous breathing trial, (b) time from randomization to successful extubation, and (c) number of ventilator-free days, defined as the number of days alive and free of mechanical ventilation during the 28 days post randomization. All patients enrolled in the study will be followed until discharge from ICU. A prior subgroup analysis is planned for patients with a high asynchrony index at baseline. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in asynchrony index from baseline | Measurement of flow, airway pressure, and estimate of respiratory muscle pressure recorded at baseline then again, at high and at low levels of support during the first seven days of the weaning protocol | Asynchrony index (percent (%) of asynchronous breaths) measured by visual inspection of flow and airway pressure tracings at baseline (just prior to randomization) and at high and low levels of support in both Proportional Assist Ventilation (PAV) and Pressure Support Ventilation (PSV) weaning algorithms. These measurements are recorded during the first seven days post randomization. |
| Change in sedative drug administration from baseline | Daily dose of sedative drugs administered at baseline and day 1, 3, and 7 of study protocol | Total dose of sedative and narcotic drugs (converted into lorazepam and morphine equivalents) administered on day 0 (baseline) and day 1, 3 and 7 of study protocol, as percentage of baseline dose |
| Delirium | Up to 28 days post randomization | Incidence of a positive delirium screening assessment (using Confusion Assessment Method - Intensive Care Unit (CAM-ICU) or Intensive Care Delirium Screening Checklist (ICDSC)) at baseline, and duration of delirium as a percentage of time in ICU post randomization. |
Other
| Measure | Time frame | Description |
|---|---|---|
| Tolerance of weaning mode | Daily, up to 28 days post randomization | Number of hours spent daily on prescribed weaning mode (PAV or PSV) |
| Indication for increased ventilatory support | Daily | Respiratory therapists will indicate on a checklist what signs of respiratory distress were present that led to an increase in level of support from the ventilator. |
Countries
Canada
Outcome results
None listed